Evolution: Gradualism and Punctuated Equilibrium

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Questions and Answers

Who wrote the book on the theory of Natural Selection?

Charles Darwin

What is the best scientific explanation for both the unity and diversity of life?

Theory of Evolution

What do we call groups of interbreeding organisms in the same area?

Population

What happens in a large population in terms of evolution?

Lower evolutionary rate, more likely to appear on the fossil record Signup and view all the answers

What happens in a small population in terms of evolution?

Easier for evolution, higher evolutionary rate Signup and view all the answers

What is evolution?

Change in variation over time Signup and view all the answers

What is natural selection?

Nature's way of selecting the best in a particular environment Signup and view all the answers

What are the four types of polygenic selection?

Disruptive Selection Signup and view all the answers

What is an adaptation?

Inherited characteristic that increases an organism's chance of survival Signup and view all the answers

What is reproductive isolation?

The inability of a species to breed successfully with related species Signup and view all the answers

What are the two main ways to describe the rate of evolutionary change?

Punctuated Equilibrium Signup and view all the answers

What is gradualism?

Change that is incremental and slow that happens over time Signup and view all the answers

Approximately how long does it take for gradualism to occur?

Millions of years Signup and view all the answers

What is punctuated equilibrium?

Pattern of evolution with long stable periods interrupted by brief periods of rapid change Signup and view all the answers

When does punctuated equilibrium occur?

Rapid change occurs when a smaller population of species are isolated from the parent population Signup and view all the answers

Approximately how long does it take for punctuated equilibrium to occur?

Hundreds of thousands of years Signup and view all the answers

Who proposed the term 'punctuated equilibrium'?

Niles Eldredge and Stephen Jay Gould Signup and view all the answers

What is a vestigial structure?

A structure that an organism has that is no longer useful to it Signup and view all the answers

What are homologous structures?

Structures that have different mature forms in different organisms but develop from the same embryonic tissues Signup and view all the answers

What are analogous structures?

A trait or an organ that appears similar in two unrelated organisms Signup and view all the answers

What is common ancestry?

A group of organisms share common descent if they have a common ancestor Signup and view all the answers

What is divergent evolution (adaptive radiation)?

Process by which a single species evolves into several different forms Signup and view all the answers

What is speciation?

Formation of new species Signup and view all the answers

What is the struggle for existence?

Competition to survive, not all of a species will survive Signup and view all the answers

What is overproduction in terms of evolution?

More will be born than can survive Signup and view all the answers

What is artificial selection?

When humans decide which characteristics will survive in a population Signup and view all the answers

What are acquired traits?

Characteristics that an organism gets during their lifetime and can not be passed on Signup and view all the answers

What is diversity in evolutionary biology?

All of the different species on Earth Signup and view all the answers

What is variation?

The differences within a single species Signup and view all the answers

What is a species?

Group of similar organisms capable of interbreeding and producing fertile offspring Signup and view all the answers

Study Notes

Key Figures in Evolution

Charles Darwin: Authored the foundational text on Natural Selection, proposing the Theory of Evolution.
Niles Eldredge and Stephen Jay Gould: Coined the term "punctuated equilibrium."

Fundamental Concepts

Theory of Evolution: A comprehensive explanation for life's unity and diversity, emphasizing descent with modification.
Population: Collection of interbreeding organisms residing in a specific locale.
Evolution: The process of change in organisms over time, leading to the adaptation and descent from ancient species.

Types of Selection

Natural Selection: Mechanism of evolution where organisms best suited to their environment thrive.
Polygenic Traits: Most traits are influenced by multiple genes, impacting evolutionary outcomes.
Types of Polygenic Selection:
- Stabilizing Selection: Favors average phenotypes by eliminating extremes.
- Directional Selection: Favors one extreme phenotype over others.
- Disruptive Selection: Favors extreme phenotypes at both ends of the spectrum.
- Sexual Selection: Selection based on traits that attract mates, leading to sexual dimorphism.

Rates of Evolutionary Change

Two main rates of evolutionary change: Gradualism and Punctuated Equilibrium.
Gradualism: Slow, incremental changes occurring over millions of years.
Punctuated Equilibrium: Characterized by long periods of stability interrupted by short, rapid changes, typically occurring in isolated populations, lasting hundreds of thousands of years.

Evolutionary Structures and Concepts

Vestigial Structures: Non-functional remnants from ancestors, demonstrating common ancestry.
Homologous Structures: Different mature forms derived from the same embryonic tissues, indicating a shared lineage.
Analogous Structures: Similar traits across unrelated species, resulting from convergent evolution rather than common ancestry.
Common Ancestry: Organisms sharing a common ancestor as a basis of evolutionary biology.

Processes in Evolution

Divergent Evolution (Adaptive Radiation): A single species evolves into multiple forms, adapting to various environments.
Speciation: The process leading to the formation of new species.
Struggle for Existence: Competition among species for survival; not all individuals will survive to reproduce.
Overproduction: More offspring are produced than can survive, leading to natural selection.

Miscellaneous Concepts

Artificial Selection (Selective Breeding): Humans choose which traits to perpetuate within populations, exemplified by domestic dogs.
Acquired Traits: Characteristics gained during an organism's life that cannot be inherited genetically.
Diversity: The range of different species occupying Earth.
Variation: Differences among individuals within a species, critical for natural selection.
Species: Groups of organisms capable of interbreeding and producing fertile offspring.

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Description

Test your knowledge on the key concepts of evolution, including the theories of gradualism and punctuated equilibrium. This quiz covers important terms and definitions associated with Charles Darwin's work and the theory of evolution. Perfect for students diving into the fundamentals of evolutionary biology!